Improvement in safety-valves



Vhave invented a new and inited tapes @anni dtiijiw.

LettersPatent No. 98,697, dated January 11, 1870.

IMPROVEMENT IN SAFETY-VALVES.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom 'it may concern.-

Be it known that I, T. S. LA FRANCE, of Elmira, in the county of Ghemung, and State of N ew York, improved Safety-Valve; and I do-herebydeclare' that the following is a full, clear, and exact description thereof, which will enable others skilled iu the art to make and use the same, reference being had to the accompanying drawing, forming part of this specication.

The drawing represents a vertical central section of my improved safety-Valve.

This invention relates to a new safety-valve for steam-boilers, and has for itsobject to adapt the valve to any desired degree of steam-pressure, so that it will be opened by the steam whenever the same will reach the said degree of pressure, and that it can also be raised off the seat by a separate apparatus, wl1enever steam is to be blown olf.

The invention consists in a novel combination, with the valve and valve-rod, of an elevating screw-cap, ashereinafter more fully described.

A, in the drawing, represents a vertical pipe, in which the annular valve, is arranged.

B is tlie safety-valve.

seat by a spiral spring, b, which is fitted around the valve-stem c, between the valve and a tubular screw,`

C, which is heid in the top plate or head rl of the pipe A.

The valve-stem fits throuffh the bore of the screw C, and can play up and down therein.

Above the head d are formed, ou the screw C, provalve-seat c, for supporting the` It is held down upon the jecting handles, e e, by means of which the screw can be turned to lower or raise it in the head, and to thereby compress the spring to a greater or lesser degree. The valve is thus held upon its seat by the spring-pressure, which can be Varied at will, in order to adapt the device to greater or lesser steam-pressure.

When the pressure exceeds the spring-power, the -valve will be raised, and the steam will pass into the upper part of the tube, whence is escapes through suitable apertures, f.

Below the valve is, screwed into the lower part of the pipe A, a shaft, D, which, with its upper end, fits against the under side of the valve, or against the'eud of a rod, g, projecting downward from the same.

By turning a handwheel, lz., at the lower end of the shaft D, the latter can be screwed up to raise the valve off the seat, Whenever it is desired to blow oti' the steam in the boiler.

`Steam enters the pipe A through a pipe, t'.

Having thus described my invention,

I claim as new, and desire to secure by Letters Patent- The safety-valve B, arranged in the pipe A, and `combined with the spring b and screw G, and with the lower screw-shaft D, substantially as described, to operate as set forth. I

lhe above specification of my invention signed by me, this 11th day of' November, 1869.

T., S. LA FRANCE.

Witnesses GEO. W. MABEE, ALEX. F. ROBERTS. 

